Fuel cell system and control method therefor

Abstract

A fuel cell system and a control method enables a smooth shift from a heat-up operation to a normal operation in a simple operating process. The fuel cell system includes a cell stack, an aqueous solution holding device having aqueous solution tanks which store aqueous methanol solution, and a first connecting portion and a second connecting portion which connect the aqueous solution tanks with each other, and a temperature sensor which detects a temperature of the aqueous methanol solution. Based on a result of a temperature detection, a setting is made for one of a first mode where the aqueous methanol solution in the aqueous solution tank is circulated to the cell stack and a second mode where the aqueous methanol solution in the aqueous solution tanks is circulated to the cell stack.

What is claimed is: 
     
       1. A fuel cell system comprising:
 a fuel cell including an anode; 
 an aqueous solution holding device including a first storing portion and a second storing portion each arranged to hold aqueous fuel solution to be supplied to the fuel cell, and a connecting portion arranged to connect the first storing portion and the second storing portion with each other; 
 a circulation device arranged to circulate a supply of the aqueous fuel solution between the fuel cell and the aqueous solution holding device by supplying the aqueous fuel solution from the aqueous solution holding device to the anode of the fuel cell and returning the aqueous fuel solution from the anode of the fuel cell to the aqueous solution holding device, the circulation device including a supply channel arranged to supply the aqueous fuel solution from the first storing portion to the anode of the fuel cell, a first return channel arranged to return the aqueous fuel solution from the anode of the fuel cell to the first storing portion, and a second return channel arranged to return the aqueous fuel solution from the anode of the fuel cell to the second storing portion without the aqueous fuel solution first passing through the first storing portion; 
 a temperature detection device arranged to detect a temperature of the aqueous fuel solution; and 
 a setting device programmed to set an amount of the aqueous fuel solution to flow through the first return channel and an amount of the aqueous fuel solution to flow through the second return channel based on a detection result from the temperature detection device; wherein 
 the second storing portion is arranged to concurrently receive the aqueous fuel solution into the second storing portion through an input pipe of the second return channel and to discharge the aqueous fuel solution from the second storing portion through the connecting portion to the first storing portion. 
 
     
     
       2. The fuel cell system according to  claim 1 , wherein the circulation device further includes a valve, and the setting device sets the amount of the aqueous fuel solution to flow through the first return channel and the amount of the aqueous fuel solution to flow through the second return channel by controlling the valve based on the detection result from the temperature detection device. 
     
     
       3. The fuel cell system according to  claim 2 , wherein the setting device selects one of the first return channel and the second return channel by controlling the valve based on the detection result from the temperature detection device. 
     
     
       4. The fuel cell system according to  claim 1 , further comprising a cooling device disposed in the second return channel and arranged to cool the aqueous fuel solution. 
     
     
       5. The fuel cell system according to  claim 1 , wherein the connecting portion includes a first connecting portion arranged to provide communication between a liquid in the first storing portion and a liquid in the second storing portion. 
     
     
       6. The fuel cell system according to  claim 5 , wherein the connecting portion further includes a second connecting portion arranged to provide communication between a gas in the first storing portion and a gas in the second storing portion. 
     
     
       7. Transportation equipment comprising the fuel cell system according to  claim 1 . 
     
     
       8. The fuel cell system according to  claim 1 , wherein the circulation device includes a switching valve, and the setting device is programmed to set the switching valve of the circulation device to a first position in which the supply of the aqueous fuel solution flows through the first return channel to the first storing portion and to a second position in which the supply of the aqueous fuel solution flows concurrently through both of the first and the second return channels, or only through the second return channel based on the detection result from the temperature detection device. 
     
     
       9. The fuel cell system according to  claim 8 , further comprising a cooling device disposed in the circulation device, the cooling device arranged to cool the aqueous fuel solution; wherein
 in the first position, the supply of the aqueous fuel solution flows through the first storing portion but not through the cooling device, and in the second position, the supply of the aqueous fuel solution flows concurrently through the cooling device and both the first storing portion and the second storing portion based on the detection result from the temperature detection device. 
 
     
     
       10. The fuel cell system according to  claim 1 , further comprising a switching valve and a cooling device disposed in the circulation device, the cooling device arranged to cool the aqueous fuel solution, wherein, based on the detection result from the temperature detection device:
 the setting device is programmed to set the switching valve of the circulation device to a first position in which the supply of the aqueous fuel solution flows from the first storing portion to the anode of the fuel cell and from the anode of the fuel cell to the first storing portion but not through the cooling device; and 
 the setting device is programmed to set the switching valve of the circulation device to a second position in which the supply of the aqueous fuel solution flows concurrently through the cooling device and both the first storing portion and the second storing portion. 
 
     
     
       11. The fuel cell system according to  claim 10 , wherein in the first position, the supply of the aqueous fuel solution flows through the first return channel, and
 in the second position, the supply of the aqueous fuel solution flows through both of the first and the second return channels, or only through the second return channel.